一个OpenMP的学习程序

贴一个学习OpenMP过程中的程序

#include <stdio.h>
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#include <tchar.h>
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#include <omp.h>
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int _tmain(int argc, _TCHAR* argv[])
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{
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Timer tm;
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// omp_set_num_threads(2),设定活动线程数为2
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omp_set_num_threads(3);
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// omp_get_num_procs()
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int procs=omp_get_num_procs();
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printf("There are %d processor(s) available!\n",procs);
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// omp_get_thread_num(),返回当前线程号;
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int Threadid=omp_get_thread_num();
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printf("当前线程号为:%d\n",Threadid);
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// omp_get_num_threads(),返回当前线程总数;
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int Threadnum = omp_get_num_threads();
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printf("当前活动线程数为:%d\n",Threadnum);
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// 并行化编译指导语句
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printf("下面开始测试并行化编译指导语句!!\n\n");
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// 1.parallel
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printf("------------------华丽无比的分隔线--------------------\n");
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printf("#pragma omp parallel\n\n");
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#pragma omp parallel
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printf("This is Thread %d say hello to you!\n",omp_get_thread_num());
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// 2.parallel for
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printf("------------------华丽无比的分隔线--------------------\n");
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printf("#pragma omp parallel for\n\n");
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#pragma omp parallel for
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for (int i=0;i<4;i++)
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{
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printf("Thread %d is active when i = %d\n",omp_get_thread_num(),i);
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}
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int i,j=0;
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// 3.parallel for private
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printf("------------------华丽无比的分隔线--------------------\n");
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printf("#pragma omp parallel for private(j)\n\n");
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printf("使用private子句\n");
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#pragma omp parallel for private(j)
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for (i=0;i<2;i++)
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for(j=5;j<7;j++)
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printf("Thread %d is active when i = %d,and j= %d\n",omp_get_thread_num(),i,j);
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printf("不使用private子句\n");
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#pragma omp parallel for
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for (i=0;i<2;i++)
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//#pragma omp parallel for
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for(j=5;j<7;j++)
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printf("Thread %d is active when i = %d,and j= %d\n",omp_get_thread_num(),i,j);
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// 4.parallel for firstprivate() and lastprivate()
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printf("------------------华丽无比的分隔线--------------------\n");
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printf("#pragma omp parallel for firstprivate and lastprivate\n\n");
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int ai=10;
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int bi=0;
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printf("Before \"parallel for \", ai = 10 ,and bi = 0 !\n\n");
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#pragma omp parallel for firstprivate(ai) lastprivate(bi)
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for (int i=1;i<4;i++)
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{
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bi=ai;
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ai=0;
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}
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printf("After \"parallel for \" bi equal to %d !\n\n",bi);
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printf("After \"parallel for \" ai still equal to %d !\n\n",ai);
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// 5.critical 临界区
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printf("------------------华丽无比的分隔线--------------------\n");
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printf("#pragma omp critical \n\n");
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int n=100000;
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int ver = 0;
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tm.start();
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#pragma omp parallel for
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for (int i=1;i<=n;i++)
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{
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//for (j=0;j<1000000;j+=2){;}
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#pragma omp critical
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ver+=i;
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//printf("Thread %d is active when i = %d\n",omp_get_thread_num(),i);
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}
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printf("ver = %d\n",ver);
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tm.stop();
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printf("%f\n",tm.elapsedSeconds());
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// 6.reduction(<op>:<variable>)
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printf("------------------华丽无比的分隔线--------------------\n");
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printf("#pragma omp reduction \n\n");
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int ver2 = 0;
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tm.start();
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#pragma omp parallel for reduction(+:ver2)
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for(int i=0;i<=n;i++)
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{
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//for (j=0;j<1000000;j+=2){;}
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ver2+=i;
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}
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printf("ver2 = %d\n",ver2);
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tm.stop();
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printf("%f\n",tm.elapsedSeconds());
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// 7.#pragma omp for
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printf("------------------华丽无比的分隔线--------------------\n");
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printf("#pragma omp for \n\n");
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//将内层for循环并行化
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#pragma omp parallel
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for (int i=0;i<2;i++)
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{
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#pragma omp for
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for (int j=0;j<2;j++)
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{
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printf("Thread %d is active when i=%d,and j=%d\n",omp_get_thread_num(),i,j);
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}
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}
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// 8.threadprivate and copyin
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printf("------------------华丽无比的分隔线--------------------\n");
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printf("#pragma omp threadprivate and copyin \n\n");
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int global=10;
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//#pragma omp threadprivate(global)
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//#pragma omp parallel
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for (int i=0;i<100;i++)
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{
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global++;
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}
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printf("Global is equal to %d\n",global);
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// 9.功能并行#prgama omp parallel sections
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printf("------------------华丽无比的分隔线--------------------\n");
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printf("#pragma omp parallel sections \n\n");
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#pragma omp parallel sections
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{
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#pragma omp section
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printf("Section 1 \'s thread is NO.%d\n",omp_get_thread_num());
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#pragma omp section
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printf("Section 2 \'s thread is NO.%d\n",omp_get_thread_num());
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#pragma omp section
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printf("Section 3 \'s thread is NO.%d\n",omp_get_thread_num());
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}
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// 10.同步编译指导语句
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// 1).同步屏障
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#pragma omp parallel
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{
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int initialization=0;
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#pragma omp barrier
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int process=1;
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}
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// 2.互斥锁机制(库函数)
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#ifdef LOCKLOCK
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#define LOCKLOCK
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omp_lock_t lock;
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//普通锁
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omp_init_lock(&lock);
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omp_destroy_lock(&lock);
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omp_set_lock(&lock);
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omp_unset_lock(&lock);
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omp_test_lock(&lock);
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//嵌套锁
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omp_init_nest_lock(&lock);
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omp_destroy_nest_lock(&lock);
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omp_set_nest_lock(&lock);
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omp_unset_nest_lock(&lock);
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omp_test_nest_lock(&lock);
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#endif
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//其他的OpenMP编译指导语句请参考OpenMP手册;
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return 0;
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}